Psyllium seed husk containing products are currently widely used for normalizing bowel function and Taxation. It has also been shown that psyllium seed husk is effective for reducing human serum cholesterol levels and in controlling blood glucose levels in diabetics.
These benefits are typically achieved by ingestion of psyllium seed husk, which is obtained from the seed coat from plants of the Plantago genus. To render a laxative effect, a typical human dose of psyllium seed husk is from about 3 grams to about 20 grams, taken from about 1 to about 3 times per day. In order to administer such a large amount of psyllium seed husk, the husk is often milled or ground and subsequently dispersed in water or an aqueous beverage for consumption by the user (for example, METAMUCIL®, sold by The Procter & Gamble Company). In addition to milling, typically, sanitization of the psyllium seed husk is performed prior to any further processing, in order to reduce microbial contamination of the psyllium seed husk. This sanitation step can be costly and difficult to perform.
Psyllium seed husk contains natural mucilage, forming a gelatinous mass on contact with water. Thus, milled psyllium seed husk, with its increased surface area, exhibits very poor disperability and mixability in water as the particles tend to agglomerate. Hydration takes place over the surface of the agglomerated aggregates to form gel-coated lumps, the interiors of which are still substantially dry. These lumps are extremely difficult to disperse. Various methods have been employed to improve the dispersability of milled psyllium husk in an aqueous medium. For example, U.S. Pat. No. 5,425,945 to Barbera, discloses a drink mix composition comprising agglomerated psyllium seed husk with an edible acid uniformly dispersed throughout the agglomerating coating to obtain improved mixability and dispersability.
However, once dispersed in an aqueous solution, the agglomerated psyllium husk quickly begins to hydrate and gel with an accompanying increase in the viscosity of the drink solution. Again, various methods have been employed to reduce this gelation rate and provide an aesthetically pleasing product. U.S. Pat. No. 5,356,618, to Daggy et al., teaches that the addition of calcium citrate malate to a composition comprising milled psyllium seed husk results in a reduced gelation rate of the husk when mixed with an aqueous solution. However, despite these improvements, the consumer of the psyllium seed husk suspension typically drinks the liquid in a relatively short period of time (less than about two minutes) in order to avoid having to drink an aesthetically unpleasant, high viscosity liquid.
Sanitized, milled psyllium seed husk has been incorporated in baked items, such as cookies, crackers and similar food items to render solid dosage forms. However, the fast gelation of the psyllium husk is noticeable in these preparations as well. Psyllium husk containing preparations have a tendency to begin to gel in the mouth during consumption, resulting in an unpleasant mouthfeel and poor aesthetics. It is generally necessary to consume such baked items with significant amounts of water or another beverage for ease of swallowing. In addition, such solid psyllium seed husk preparations must be large in size or, alternatively, multiple preparations must be consumed in order to deliver an effective amount of psyllium seed husk. Therefore, a psyllium containing composition that is convenient, easily administered and has acceptable aesthetics and good mouthfeel characteristics is still needed.
Previously the focus has been to provide a swallowable psyllium-containing tablet with acceptable dissolution properties, thus avoiding problems of poor mouthfeel. U.S. Pat. No. 4,999,200, to Casillan, teaches a swallowable psyllium-containing tablet comprising psyllium, a binder, a wetting agent and a disintegrating agent. Unfortunately, swallowable psyllium tablets, while convenient, often have poor dissolution properties. Like the powdered drink mix, once introduced into an aqueous environment hydration takes place over the surface of the pill, creating a gel coating, the interiors of the pill remain substantially dry. For swallowable pills this can lead to incomplete dissolution in the gastrointestinal tract. Therefore, there is a need to provide a psyllium-containing dosage form, suitable for chewing, where the chewing action disintegrates the tablet into smaller, discrete particles prior to swallowing but which undergoes minimal gelling in the mouth, and has acceptable mouthfeel and good aesthetics as perceived by the consumer.
Methods of fractionating psyllium seed husk into various polysaccharide components are known. These fractions of psyllium seed husk deliver the same therapeutic benefits as psyllium seed husk and can act as a suitable substitute for psyllium seed husk in various dosage forms. For example, U.S. Pat. No. 6,287,609 to Marlett et al., teaches a multiple extraction process for obtaining three distinct fractions from psyllium husk, including an alkali soluble/acid gel-forming fraction, an alkali insoluble fraction, and an acid soluble fraction. The alkali soluble/acid gel-forming fraction has a slower rate of gelation than non-fractionated psyllium seed husk.
It has been surprisingly discovered that the use of a gel-forming polysaccharide derived from psyllium seed husk, when combined with certain excipients that are fast dissolving in saliva, renders an oral composition that undergoes minimal gelling in the mouth of the consumer prior to swallowing and has good aesthetics.
It has also been discovered that combining a comparatively slow dissolving excipient at relatively low levels with the gel-forming polysaccharide and the fast dissolving excipient, results in an oral compositions with improved aesthetics and better mouthfeel as perceived by the consumer.